[X] My Assistant

[Bjorn Jonsson]

I have been attempting to make computer generated images of the Martian atmosphere, both as seen from the surface and from space. To check the results I have been looking for spacecraft images to use as ground truth. I have found lots of images - by far the best ones I have found are from UMSF in this thread: http://www.unmannedspaceflight.com/index.php?showtopic=3324

However, I'm always looking for more ;-). So if anyone knows of more and/or better images I'm interested in them. What would be best are mosaics showing the sky from the horizon (with the horizon/surface visible) and towards the zenith.

The sky varies a lot because of variable amount of dust but the general impression I get is that the sky is bright near the horizon (usually brighter than the surface) but gets much darker higher in the sky. There is probably a fairly large, bright area in the sky near the sun, possibly less reddish (lower R/B ratio) than parts of the sky farther from the sun.

I'm already getting fairly interesting results, this one has a field of view of 90 degrees:


(needless to say this one is 'overexposed' near the horizon; dynamic range is sometimes a problem)

The problem is that even though this may not be bad the limb currently appears far too bright as seen from space :



This shows that my atmospheric model is erroneous in some way - I suspect that as seen from the surface the Martian sky is darker high above the horizon than I have been assuming.

[Ant103]

The first image seems very good for me. Don't know if you know, but with Terragen you can made very good sky, with various parameters like intensity of atmospheric scattering, or dust opacity (and color).

Don't know if it's accurate but I like make "artificial" skies like here :




You can also have a look on this galery of picture from Olivier : http://www.planete-mars.com/goursac/2006/vision2.html

[djellison]

with Terragen

I've dabbled with Terragen, but not much. It would save a LOT of rendering time to pre-render a nice sky like that in Terragen, then map that to a sky hemisphere in 3ds max rather than using Dreamscape. Do you have a save file for that Terragen render as a starting point (or a list of parameters)